The Supreme Court has agreed to weigh whether former President Trump is immune from prosecution — a historic case with profound implications for the court, the 2024 election and the presidency itself.

Why it matters: The court's decision to hear Trump's appeal will further delay the Justice Department's prosecution of the former president over his role in Jan. 6.

• The federal case is one of the most serious legal threats that Trump is facing while campaigning for another term in the White House.

Catch up quick: As Trump has tried to avoid going to trial over the Jan. 6 charges, his lawyers laid out a sweeping theory that no president can be prosecuted for actions taken as president, even after they leave office.

• Trump's lawyers argued in a lower court that even if a hypothetical president ordered the military to assassinate a political rival, they could not be prosecuted.
• That court, the D.C. Circuit Court of Appeals, rejected Trump's argument, ruling that former presidents can be prosecuted after they leave office.
• Trump then appealed that decision to the Supreme Court, which agreed Wednesday to consider the case. Oral arguments have not yet been scheduled.

The stakes: Trump's theory would essentially put presidents above the law, the Justice Department has argued.

• Lawyers for the GOP presidential frontrunner have said that if he's not immune from prosecution here, every president will face a barrage of politically motivated criminal charges as soon as they leave office.
• How the justices decide that question will have profound implications for every future president and for the public's already-waning trust in the Supreme Court as an institution.

What they're saying: Trump responded to the Supreme Court's announcement in a statement saying that without presidential immunity, "a President will not be able to properly function, or make decisions, in the best interest" of the U.S.

• "Presidents will always be concerned, and even paralyzed, by the prospect of wrongful prosecution and retaliation after they leave office. This could actually lead to the extortion and blackmail of a President," he added.
• "A President has to be free to determine what is right for our Country without undue pressure. If there is no Immunity, the Presidency, as we know it, will 'no longer exist.'"

What we're watching: It remains to be seen whether Justice Clarence Thomas will recuse himself from the case.

• He may have a potential conflict of interest since his wife, Ginni Thomas, played an active role in encouraging then-White House chief of staff Mark Meadows to help overturn the 2020 election results.
• Ginni Thomas also exchanged emails with John Eastman, an ex-Trump lawyer who championed the legal theory that the former president used to try to pressure Mike Pence to overturn the 2020 election results.

Flashback: Justice Thomas previously recused himself from the court's decision on a case involving Eastman.

State of play: The Supreme Court has taken up another Jan. 6-related case that may affect the case against Trump.

• It decided in December to hear an appeal from a defendant charged with obstructing an official proceeding for entering the Capitol on the day Congress met to certify President Biden's victory.
• How the court interprets the application and definition of that statute could upend cases against hundreds of other Jan. 6 defendants, including Trump, who was charged with the same crime.

Go Deeper: What to know about Trump's immunity claim in the 2020 election case

Editor's note: This article has been updated with new details throughout.